The women I dive with get 60 mins dive time on less than half a tank, on a max 90 foot depth dive, but usually either get cold or need to use the head and are fussy about just going in their wetsuits. Tell her the water temps are high 80s and she only needs a shorty or get her to drink a lot of fluids. If neither of those work, remember Its important to do a buddy check. Just before splashing in, turn her air on and depress her second stage to make sure its flowing...if you kind of casually stop the runaway flow, you're only just making sure her air is on.